Improvement in hot-air furnaces



anni Seite vn/'ILLIAM n. nanrtnrr, or AMESBURY, MASSAcHUSnrTs.

Letters Patent No. 110,889, dated January 10, 18,71.

IMPROVEMENT IN HOT-AIR FURNACES.

The Schedule referred to in these Letters Patent and malng part offtlie same.

To all whom it may concern.-

tion of my invention sufficient to enable those skilled.

in the art to practice it.

This furnace is`con1posed of masonry, in which are set a suitable fire-pot and air-fines of ine-tal, the design being to p mduceav simple and effective heatingapparatus,which can be made of any size suited to the size of the tire-pot employed, without the need of having expensive patterns and castings for different sizes of furnaces, in which apparatus there are no joints other than such as can be made by any mason with mortar and cement, and no red-hot surfaces of iron to render the heated air unpleasant tothe senses.

In this furnace I introduce a means for supplying heated air in fine jets directly over the incandescent fuel, so that it mingles with the smoke and liberated gases, causing their perfect combustion.

The* tire-pot is composed of metal, lined with firebrick, soap-stone, or -other suitable refractory material, the whole tire-pot being so mounted in masonry as to leave, between the outside of the pot vand the wall which supports andV surrounds it, an air-space, from which the air, heated by conduction and radiation from the fire-pot, may pass through the grate and the fuel therein, or into theA combustion-chamber and" space above the' fuel.

rl`he chamber into which the smoke and gases pass is made by walls and a top of masonry, and in two of the opposite walls are set ues of metal, which I prefer to make of an oval form of section, arranged with the long diameter of each in a vertical position.

These tlues ,are open at both ends, and opposite the ends of the flues on one side a wall` is built', leaving a space between it and the line-supporting wall, which is divided by horizontal partitions, beneath the lower one of which cold air is admitted, which becomes heated by passing through the hues.` Opposite the other ends of the ue's another wall is built, leaving an air-space between it and the flue-supporting wall, this space being also divided by horizontal partitions alternating with those above named, the top of the furnace, and preferably,'also, around the ends thereof, so as to prevent waste of heat from the end walls of the combustion-chamber; and from the space over the furnace the hot air is taken for distribution through suitable pipes. A I place at the rear of the fire-pot, inclining upward and toward the fuel-door, a pl( te of soap-stone, re-

brick, or other suitable refractory material, and, by means 'of a dishing-plate securedeto the back of the soap-stone, I form a chamber linto which air is admitted through a pipe. The soap-stone is drilled withv numerous holes of about an inch in diameter, aud-the holes are groovedand then lled with cylindrical plugs of suitable refractory material, thus leaving numerous small air-passages through which thev air introduced through the pipe escapes over the fuel, being highly heated on its passage.` -'.lhe fine holes' for the passage of air may be otherwise made, but I have described the most practical and convenientmethod known to' me. i. v

From the, combustion-chamber, which receives the heat, smoke, and gases generated by the consumption of fuel, two outlet-pipes lead to one funnel, leading to the chimney, one outlet-pipe being near the upper part, and the other being near the lower part of thel Vcombustion-chamber, the former giving `a direct draught, to be used in starting a're, and the other an indirect draught, to be used after atire is established, there being a controlling' damper in the direct outlet. y

Referring to the drawing for further description- Figure l shows my improved furnace in vertical longitudinal section;

Figure 2 shows the same in cross vertical section, the sectional plans of each figure being denoted by dotted lines on the other ligure f Figure?) is a detailed view of a portion of the surface of the perforated plate of the gas-burning appara'tus; and l Figure 4 shows a diaphragm, which 'I sometimes introduce into the cold-air ends of some of thelower flues to lessen the amount of flow of air through them.

a is the wall which forms the ash-pit, `and which .supports the flanged wmetal of the hre-pot, which is provided with a refractory lining, b,- and a suitable shaking and dumpinggrate, c.

Side walls d d', and front and rear walls e and f,- are erected, as shown, the flues g being built into the walls d d', and -making passage-ways for air ,to pass from the space formed between the walls d and h, into the space between the walls d" and i, and nice versa,

the cold air first passing through the lower series of I tubes, then in the opposite direction through the next higher series, and so ou alternately, metal partitions 1 l l serving to compel the air'to take this winding or circuitous path before reaching the hot-air chamber.

lhe walls dd', f, and e, are lower than the walls h and i, and are covered by atop, j, which extends from the wall d' to the wall h, the walls f and e also extending to the wall h..

A less perfect construction is to dispense with the or of tire-clay or other refractory material, and of any cuter end air-spaces and walls land ou, continuing the walls c and f to the top, 7s, the outlet-distributing pipes a a n leading from the space between the tops j and lo. l

o is the direct-draught outlet, and

p, the indirect-draught outlet, both conununicating with the funnel q, there being a damper in o, by which the outgoing passage of smoke, 85e., is controlled.

An air-chamber which has a front plate, r, of soapstone or other suitable refractory material, and a dishingv-back, ot' copper, preferably, rests with its lower edge across the rear ot' the fire-pot, the plate r projecting upward and inclining-toward the fuel-door.

4This plate is perforated, preferably 'by boring, thenl the round holes are grooved, and cylindrical plugss, are driven into the holes, thus leaving small escapepassages for the air, which, through pipe t, enters the chamber formed at the back of plate r.

It will be seen that all the products of combustion are thrown off from the fuel directly into the large chamber which is traversed by the lines g, that cold air entering the space between d and h, or between d and t', as the case may be, passes through the lower ilues, is heated in its wimlingf-passage through the other ilues, and is distributed from and through pipes n.

The tlues may be made of cast or wrought metal,

desired form, and the size of the furnace may be enlarged or diminished at will, -by merely increasing or diminishing the walls, and the number of lnes and the size of the fire-pot, so that such furnaces may be made in regions remote from foundries and where transportation is expensive.

The gas-burner is located where it will become intensely heated, and where it discharges fine jets of highly-heated air directly upon and -into the consumable volatile products escaping from the fuel, resulting in the ignition of said products and their consumption with a brilliant flame, thus utilizing the ealoritie yalue of the fuel to the greatest possible extent.

Ashes and other solid matter fall in the lnelchamv ber below the fines, where the deposit remains until cleaned out, without obstructing the draught or lessening the eilicieney of the conducting and radiating surfaces. The tlues are shown as horizontal in their location, but they might be inclined upward.

I claim- 1. rlhe furnace as made, with a combustion-chamber located with respect to the fire-ppt, as shown and described, when the combustion-chamber is uneucumbered with tortuons or contracted passages between the fire-pot andthe direct or indirect smoke outlet, and when it is traversed by air-fines which are surrounded by the heated and volatile products of combustion proceeding from the fuel, through the lower series of which lues passes cold air from a cold-air chamber on one side of the furnace, and thence back and forth alternately through each ser-ies of filles, to a hot-air chamber llocated over its top, the air being Yheated in its passage through thc llues, the whole heilig arranged and combined substantiallyas described.

2. The plate roi' the air-heating chamber, in whicll" the air-discharge passages are made by and between perfor-ations through the plate and plugs which are located in such perfor-ations.

WM.y D. BARTLETT,

Witnesses:

S. F. Uranium, N. O. Sawrnn. 

